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Re: Re: Collect exponents only

• To: mathgroup at smc.vnet.net
• Subject: [mg101415] Re: [mg101405] Re: [mg101385] Collect exponents only
• From: Jack L Goldberg 1 <jackgold at umich.edu>
• Date: Sun, 5 Jul 2009 23:17:08 -0400 (EDT)
• References: <200907050847.EAA27265@smc.vnet.net>

Collect[expr,x] seems to work on my Mac using Version 7.?

Jack

Quoting Bob Hanlon <hanlonr at cox.net>:

>
> expr = A Exp[I (x + y) - I x] + A^2 Exp[I (x + y) - I y];
>
> expr /. Exp[z_] :> Exp[Simplify[z]]
>
> A^2*E^(I*x) + A*E^(I*y)
>
> Map[Simplify, expr, {2}]
>
> A^2*E^(I*x) + A*E^(I*y)
>
>
> Bob Hanlon
>
> ---- Francisco Rojas <fjrojas at gmail.com> wrote:
>
> =============
> Hello,
>
> I was wondering if there's anyway to ask the command Simplify (or
> maybe some other command) to only collect terms in the exponents of a
> long expression (which contains complex exponentials by the way) and
> not perform any other kind of simplification.
>
> For example I have an expression like this:
>
> A Exp[ I (x+y) - I x] + A^2 Exp[ I (x+y) - I y]           ( I is the
> the imaginary unit )
>
> Mathematica does two simplications here: it simplifies the terms in
> the exponents and factors out the A giving:
>
> A (Exp[ I y] + Exp[I x])
>
> whereas I would like to obtain only the exponents simplification,
> i.e.   A^2 Exp[ I y] + A Exp[ I x]
>
> Anybody knows how to do this?
> Thanks in advance,
> Francisco
>
>
>
>
>
>

• References:
  • Re: Collect exponents only
    • From: Bob Hanlon <hanlonr@cox.net>